Oil soluble hyperbranched polyesteramides

ABSTRACT

The invention relates to a method to produce a modified hyperbranched polyesteramide, containing at least two β-hydroxylamide ester groups and optionally also a hydroxyalkylamide endgroup, wherein (a) a hydroxy-, or aminefunctional monomer, oligomer or polymer is contacted with a first molar excess of a cyclic carboxylic acid anhydride, forming a mixture of an acid functional ester, respectively an acid functional amide and a cyclic carboxylic acid anhydride; (b) the mixture is contacted with an amount of alkanediolamine, wherein the amount is a second molar excess with respect to the first molar excess. The invention further relates to a modified hyperbranched polyesteramide containing at least two β-hydroxylamide ester groups and optionally also a hydroxyalkylamide endgroup with a degree of polymerisation of more than 19, as well as the use of these polyesteramides as rheology modifier in gas-oil or in diesel.

The invention relates to a method to produce a modified hyperbranchedpolyesteramide, containing at least two β-hydroxylamide ester groups andoptionally also an hydroxyalkylamide endgroup.

The invention relates in particular to a method for the manufacturing ofa modified hyperbranched polyesteramide according to formula (1):

D=(C₂-C₂₄), aryl or (cyclo)alkyl aliphatic diradical, optionallysubstituted,

wherein

-   -   X² can be X¹, and terminates with at least —H,        and optionally also    -   R¹, R², R³, R⁴, R⁵ and R⁶ may be H, (C₆-C₁₀) aryl or        (C₁-C₈)(cyclo)alkyl radical, OR₇ is derived from a        hydroxyfunctional monomer, oligomer or polymer, wherein R₇ can        be aryl, alkyl, cycloalkyl, or the radical of polyethyleneoxide,        polypropyleneoxide, poly tetrahydrofurane, or a nylon oligomer,        R₈ and R₉ may, independently of one another, be chosen from the        group of, optionally hetero atom substituted (C₆-C₁₀)        arylgroups, or optionally heteroatom substituted (C₁-C28)        alkylgroups and C(O)R₁₀ is derived from a monomeric, oligomeric        or polymeric monofunctional carboxylic acid.

Suitable carboxylic acids are, for example, saturated aliphatic (C₁-C₂₆)acids, unsaturated (C₁-C₂₀) fatty acids, aromatic acids andα,β-unsaturated acids.

Suitable saturated aliphatic acids are for example acetic acid,propionic acid, butyric acid, 2-ethyl hexanoic acid, laurylic acid andstearic acid.

Examples of suitable α,β-unsaturated acids are (meth)acrylic acid,crotonic acid and monoesters or monoamides of itaconic acid, maleicacid, 12-hydroxystearic acid, polyether carboxylic acid, and fumaricacid.

Suitable aromatic acid are for example benzoic acid and tertiairy butylbenzoic acid.

R₁₀ can be chosen from, for example, a saturated or unsaturated (C₁-C₄₀)alkyl or aromatic group, a polymer or an oligomer. Examples of suitablepolymers are polyesters, polyethers and poly(capro)lactones.

R₁₀ can be substituted with for example ester groups, ether groups,amide groups and alcohol groups.

A method for the manufacturing of these hyperbranched polyesteramides isknown from WO-A-00/58388. WO-A-00/58388 describes a method to producethe modified hyperbranched polyesteramide by reacting an alkanediolaminewith a molar excess of a cyclic anhydride or diacid to form ahydroxyalkylamide at a temperature between 20° C. and 120° C., afterwhich an acid terminated polyesteramide is obtained by polycondensationat a temperature between 120 and 250° C.

A modified hyperbranched polyesteramide is obtained by reacting the acidterminated polyesteramide with a monomer, oligomer or polymer containingreactive groups that can react with the carboxylic acid groups.

A disadvantage of this method is, that the modified polymers alwayscontain a certain amount of di-acids or di-esters. The presence of thesemoieties has a negative effect in many applications of the modifiedhyperbranched polyesteramide. In high temperature oil applications forexample these low molecular mass molecules easily evaporate, whichfrustrates the viscosity regulation of the oil.

The object of the invention is to provide a method to produce a modifiedhyperbranched polyesteramide without substantial amounts of di-acids ordi-esters.

According to the invention, this object is achieved in that

-   -   (a) a hydroxy-, or aminefunctional monomer, oligomer or polymer        is contacted with a first molar excess of a cyclic carboxylic        acid anhydride, forming a mixture of an add functional ester,        respectively an add functional amide and a cydic carboxylic add        anhydride;    -   (b) the mixture is contacted with an amount of alkanediolamine,        wherein the amount is a second molar excess with respect to the        first molar excess.

With the method according to the invention no substantial amounts ofdi-acids or di-esters are present in the modified hyperbranchedpolyesteramide.

The temperature at which the hydroxy-, or aminefunctional monomer,oligomer or polymer is contacted with the cyclic carboxylic acidanhydride (step a.) is not critical but will be in general between roomtemperature and 80° C. Preferably the temperature will be about 60° C.Then the mixture is heated to a reaction temperature between 140° C. and200° C. The addition of alkenediolamine in step b. in general is carriedout at the reaction temperature of the reaction mixture in step a. Ingeneral the reaction between the acid anhydride and the alkanediolamineis fast, and is followed by the esterification reaction, which proceedstypically in 4-20 hours.

In the known method for the manufacturing of a modified hyperbranchedpolyesteramide the degree of polymerization depends on the ratio ofalkanediolamine (hereinafter referred to as B₃) and cydic anhydride ordi-add (hereinafter referred to as A₂). With less excess of the cyclicanhydride a higher degree of polymerization is obtained.

The disadvantage of the thus prepared hyperbranched polyesteramide is,that degree of polymerization is limited to 19. From an article by DirkMuscat and Rolf A. T. M. van Benthem; “Hyperbranched Polyesteramides—NewDendritic Polymers, Topics” in Current Chemistry, Vol. 212, 2001,p.42-80, it can be derived that it is impossible to make a modifiedhyperbranched polyesteramide with a degree of polymerization of morethan 19 as this will result in gelation of the hyperbranchedpolyesteramide. Hereinafter the following definition of the functionalgroups will be used: A for a carboxylic goup and B for an hydroxide or asecondary amine group.

According to above-mentioned article, which is included herein byreference, scheme 1, p.57, the system with an excess of A₂ and fullconversion of the B groups, results in a mixture of —hyperbranched’molecules (i.e. molecules containing at least one A-B bond) andunreacted A₂ monomers.

Starting with 2n+1 moles of A₂ and n moles of B₃, for n=1, the molarratio in a reaction mixture of A₂ and B₃ for a reaction between a cyclicanhydride and a alkanediolamine is 3:1 and gelation will occur with thefull conversion of the B groups. For values of n>1, gelation ispredicted to occur before all B-groups have reacted, for n<1 gelation isnot expected to occur.

For n=1, 2n+1=3 moles of A₂ and 1 mole of B₃ are present in the reactionmixture. At full conversion of the B-groups, neglecting the gelation andintramolecular reactions, there are 3 moles of A-B bonds. Each A-B bondimplies that the number of molecules is reduced with 1, and therefore,(3+1)−3=1 moles of molecules are left. Since the reaction started with3+1 moles, the average degree of polymerization (including the unreactedA₂) is equal to 4.

According to scheme 1 in the article, the fraction of unreacted A₂equals ((n+2)/(4n+2))²=0.25. So, there are 0.25*3=0.75 moles ofunreacted A₂ in system, each having a degree of polymerization of 1. Theamount of ‘hyperbranched’ molecules is therefore 1−0.75=0.25 moles, andare built from (3+1)−0.75=3.25 monomers. So, the average degree ofpolymerization is 3.25/0.25=13.

By an equivalent reasoning, one can deduce that the average number ofunreacted A-groups in the hyperbranched molecules equals 6. So, whenfully functionalized, the maximum degree of polymerization equals13+6=19. Herein the degree of polymerization is applied to the‘hyperbranched’ molecules only, neglecting unreacted A₂ molecules.

Preferably in the method of the invention the first molar excess is atleast 50% and the second molar excess is at most 33.3%.

This results in modified hyperbranched polyesteramide with a degree ofpolymerization greater than 19.

The invention therefore also relates to modified hyperbranchedpolyesteramides according to formula 1 with a degree of polymerizationgreater than 19.

An advantage of the method according to the invention is that the degreeof polymerization basically has no limitation.

The disadvantage of the hyperbranched polyesteramides described inWO-A-00/56804 is that they are generally insoluble or poorly soluble inoil, while branched polymers may improve the rheological properties ofoil.

A further object of the invention therefore is to provide ahyperbranched polyesteramide that is soluble in oil. Under ahyperbranched polyesteramide that is highly soluble in oil in thisdescription is understood a hyperbranched polyesteramide dissolvable inhexane, mineral oil, diesel and vegetable oil. Preferably thehyperbranched polyesteramide is dissolvable in hexane in an amount of atleast 5% by weight at room temperature.

According to the invention, this object is achieved in that D is anoptionally substituted diradical [C]—C₅, wherein [C] is the diradical,C_(s) the substituted group and s being the number of C-atoms in thesubstituted group equals or is greater than zero, the hydroxy- or aminefunctional monomer, oligomer or polymer HOC_(t), or H₂NC_(t) has tC-atoms, with t≧1 and T₁+T₂>4, with T₁=s,T₂=tkp_(COOH)/(2m+3q−p_(COOH)m), wherein k is the amount ofmolequivalents of C_(t), m is the amount of molequivalents of D, andp_(COOH)={(m+k−M.AC/56100)/(m+k)}, wherein M is the total mass (in g) ofthe hyperbranched polyesteramide and AC is the acid value in mg KOH/gresin.

In this formula the amount of starting materials are taken as k moles ofC_(t)-(B*a)A* (monoacid), m moles of A-(ab)B₂ and q mole of B₂b, withC_(t)-(B*a)A* the reaction product of HOC_(t), abbreviated as B-C_(t)and a cyclic anhydride abbreviated as aA*, A-(ab)B₂ the reaction productof bB₂, an alkanediolamine and aA a cyclic anhydride.

D may be saturated or unsaturated. D may be substituted with for examplea (C₁-C₂₆) alkyl group, which may be saturated or unsaturated;

D may be for example a (methyl-)1,2-ethylene [s=1],(methyl-)1,2-ethylidene [s=1], 1,3-propylene [s=0],(methyl-)1,2-cyclohexyl [s=5], (methyl-)1,2-phenylene [s=5],2,3-norbornyl [s=7], 2,3-norbornen-5-yl [s=7] and/or (methyl-)1,2cyclohex-4-enyl [s=(5)4] radical.

Depending on the starting monomers chosen, the variables D, R¹, R², R³,R⁴, R⁵ and R⁶ in the molecule or mixture of molecules can be selected tobe the same or different.

The polymer composition according to the invention is generally acomposition comprising higher and lower oligomers, which usuallycontains less than 50 wt. %, preferably less than 30 wt. %, of oligomershaving a molecular weight smaller than 500 g/mol.

This causes the oil soluble hyperbranched polyesteramides to have a highboiling point, which favours the use of these materials in oil at hightemperatures.

The advantage of the oil soluable hyperbranched polyesteramide of theinvention is, that it contains no significant amount of monomericesters. The presence of monomeric esters strongly disturbs the use ofhyperbranched polyesteramides as a material to adjust the viscosity ofoil.

The invention further related to the use of the hyperbranchedpolyesteramides according to the invention in gas-oil as rheologymodifier or in diesel as anti freeze agent and to catch metals and soot.

An advantage of the use of the hyperbranched polyester amides of theinvention as rheology modifier in oil is that no substantial amounts ofdi-acids or di-esters are present.

Hereinafter some Examples and Comparative Experiments will elucidate theinvention without being limiting.

EXAMPLE I

422.9 g of mono-hydroxyl polyethylene oxide, a mono-disperse oligomerwith M_(n)=350 g/mol. is added to 292.4 g of hexahydrophthalic anhydridewith a molar mass of 154.16 g/mol at room temperature whereafter themixture is heated to 180° C. The mono-hydroxyl polyethylene oxide (1.21mol) reacts at 180° C. during 0,5 hour with hexahydrophthalic anhydride(1.90 mol) yielding 1.21 mole of a mono-acid functional ester (with amolar mass of 350+154.16=404.16 g/mol, denoted by C_(t)-A) and 0.69 moleof hexahydrophthalic anhydride that has not reacted at the end of step(a).

In step (b), 114.8 g of diisopropanolamine (DIPA, with a molar mass of133.19 g/mol, being 0.86 mol and denoted by B₃) is added to the reactionmixture of step (a.). First DIPA reacts with the unreactedhexahydrophthalic anhydride this being a fast reaction, yielding 0.69mol of mono-acid-di-hydroxyl functional units (molar mass of these AB₂units being 154.16+133.19=287.35 g/mol) and 0.17 mole of DIPA that hasnot reacted. Then esterification occurs in step b during 10 hours,wherein the AB₂ units react with itself thus forming a hyperbranchedmolecule and with the mono-acid functional ester formed in step a.

The acid number at the end of step (b) is 23.1 mg KOH/g resin, which isequivalent to a conversion p_(COOH) of 0.85. This corresponds to adegree of polymerization of the obtained hyperbranched polyesteramide of13.2. The degree of polymerization (P_(n)) is calculated in thefollowing way. Denote the acid groups by A and the hydroxyl/amine groupsby B. At the start of the esterification we have k=1.21 mole ofmono-acid C_(t)-A, m=0.69 moles of AB₂ units and q=0.17 moles of B₃units. At conversion p_(A) a number of (k+m)p_(A) ester bonds have beenformed. Every bond decreases the number of molecules by one. So,k+m+q−(k+m)p_(A) molecules are left at conversion p_(A) (0.85). Fromthese molecules, (1-p_(A))k molecules are mono-acid molecules that havenot reacted. These are excluded in the computation of P_(n), so weconsider only k+m+q−(k+m)p_(A)−(1−p_(A))k molecules. These are builtfrom 2k+2m+q−(1−p_(A))k monomeric units, where the factor 2 for k and mcomes from the fact that the mono-acid and the mono-acid-dihydroxylunits are reaction products and consist of two monomeric units. Theratio of the built-in monomeric units over the number of molecules givesP_(n).

The mono-acid-di-hydroxy-functional units have 4 C-atoms ‘outside’(originating from the hexahydrophthalic anhydride, so s=4 and T1=4.

The mono-hydroxyl polyethylene oxide oligomer is considered to consistof 7.5 monomeric units with 2 C-atoms per monomer, so t=15 andT2=0.789×t=11.8.

This material dissolves well in hexane.

EXAMPLE II

445.0 g of mono-hydroxyl polyethylene oxide. with M_(n)=550 g/mol (0.81mol). Is added to 248.0 g of hexahydrophthalic anhydride (1.61 mol). Themono-hydroxyl polyethylene oxide reacts with the hexahydrophthalicanhydride yielding 0.81 mole of a mono-acid functional ester (molar massis 550+154.16=604.16 g/mole) and 0.80 mole of anhydride that has notreacted at the end of step (a).

In step (b), 106.9 g of DIPA is dosed (molar mass is 133.19 g/mole),i.e., 0.803 mole. The DIPA preferably reacts with the availableanhydride yielding 0.80 mole of mono-acid-di-hydroxyl functional units(molar mass of these units is 154.16+133.19=287.35 g/mole) and 0.003mole of DIPA that has not reacted. Then esterification occurs ending upwith an acid number at the end of step b of 13.5 mg KOH/g resin, whichis equivalent to a conversion p_(COOH) of 0.88. This corresponds to adegree of polymerization of the obtained hyperbranched polyesteramide of31.7.

The mono-acid-di-hydroxy-functional units have 4 C-atoms ‘outside’(originating from the hexahydrophthalic anhydride, so s=4 and T1=4.

The mono-hydroxyl polyethylene oxide oligomer is considered to consistof 12 monomeric units with 2 C-atoms per monomer, so t=24 andT2=0.779×t=18.7.

This material dissolves well in hexane.

Comparative Experiment A

A double-walled glass reactor was charged with 100.0 g of moltendiisopropanolamine [40° C]. 362.1 g of adipic acid were added, thereaction mixture was heated 180° C. After three hours at thistemperature the pressure in the reactor was lowered to 2 mPA. After atotal reaction time of 6.5 hours, the polymer was cooled and obtained asa viscous resin. The acid value was 365.3 mg KOH/g resin. 244.0 g of theabove described resin were further reacted with 300.0 g dodecanol in adouble-walled glas reactor. The reaction mixture was for 5.5 hours at180° C., then the pressure was lowered to 2 mPa. After 10 hours reactiontime the polymer was cooled and obtained as a viscous resin. The acidvalue was 10.8 mg KOH/g resin. This corresponds to a conversionp_(COOH)=0.965 and a degree of polymerization of 4.9. The rest amountsof not reacted di-acid is 0.25% (mole/mole) and the amount of diesterequals 63% (mole/mole).

Comparative Experiment B

A double-walled glass reactor was charged with 114.8 g of moltendiisopropanolamine [40° C]. 292.4 g of hexahydrophthalic anhydride wereadded, followed by 422.9 g of mono-hydroxyl poly(ethylene oxide)oligomers [Mn appr. 350]. The reaction mixture was heated 180° C. Afterten minutes gelation occurs. This shows that the sequence of adding thedifferent components is extremely important.

1. Method for the manufacturing of a modified hyperbranchedpolyesteramide according to formula (1):

D=(C₂-C₂₄), aryl or (cyclo)alkyl aliphatic diradical, optionallysubstituted,

X² can be X¹, and terminates with at least —H,

and optionally also

R¹, R², R³, R⁴, R⁵ and R⁶ may be H, (C₆-C₁₀) aryl or (C₁-C₈)(cyclo)alkylradical, OR₇ is derived from a hydroxy-, or amino functional monomer,oligomer or polymer, wherein R₇ can be aryl, alkyl, cycloalkyl, or theradical of polyethyleneoxide, polypropyleneoxide, polytetrahydrofurane,or a nylon oligomer, R₈ and R₉ may, independently of one another, bechosen from the group of, optionally hetero atom substituted (C₆-C₁₀)arylgroups, or optionally heteroatom substituted (C₁-C₂₈) alkylgroupsand C(O)R₁₀ is derived from a monomeric, oligomeric or polymericmonofunctional carboxylic acid, characterized in that (a) the hydroxy-,or amino functional monomer, oligomer or polymer is contacted with afirst molar excess of a cyclic carboxylic acid anhydride, forming amixture of an acid functional ester respectively an acid functionalamide and a cyclic carboxylic add anhydride; (b) the mixture iscontacted with an amount of alkanediolamine, wherein the amount is asecond molar excess with respect to the first molar excess.
 2. Methodaccording to claim 1, wherein the first molar excess is at least 50% andthe second molar excess is at most 33.3%.
 3. Modified hyperbranchedpolyesteramide according to formula 1 in claim 1, wherein the degree ofpolymerization is more than
 19. 4. Modified hyperbranched polyesteramideaccording to claim 3, wherein D is an optionally substituted diradical[C]—C_(s), wherein [C] is the diradical, C_(s) the substituted group ands being the number of C-atoms in the substituted group equals or isgreater than zero, the hydroxy- or amine functional monomer, oligomer orpolymer HOC_(t) or H₂NC_(t) has t C-atoms, with t≧1 and T₁+T₂>4, withT₁=s, T₂=t.kp_(COOH)/(2m+3q−p_(COOH)m), wherein k is the amount ofmolequivalents of C_(t), m is the amount of molequivalents of D, andp_(COOH)={(m+k−M.AC/56100)/(m+k)}, wherein M is the total mass (in g) ofthe hyperbranched polyesteramide and AC is the acid value in mg KOH/gresin.
 5. Use of hyperbranched polyesteramides according to the claim 3in gas-oil as rheology modifier, or in diesel as anti freeze agent andto catch metals and soot.